Multi-layered Foamed Polymeric Objects and Related Methods
AssigneesDart Container Corporation, University of Washington
InventorsKrishna Nadella, Gregory Branch, Vipin Kumar, Michael A. Waggoner
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AssigneesDart Container Corporation, University of Washington
InventorsKrishna Nadella, Gregory Branch, Vipin Kumar, Michael A. Waggoner
Estimating the term…
The invention disclosed herein relates to relates to foamed thermoplastic material objects and articles of manufacture having an internal layered cellular structure, as well as to methods of making the same. In one embodiment, the invention is directed to a multi-layer foamed polymeric article of manufacture, comprising: a non-laminated multi-layer thermoplastic material sheet, wherein the multi-layer thermoplastic material sheet has first and second discrete outer layers sandwiching a plurality of discrete inner foamed layers, and wherein the two outer layers and plurality discrete inner foamed layers are integral with one another. The thermoplastic material may be a semi-crystalline polymer such as, for example, PET (polyethylene terephthalate), PEEK (polyetheretherketone), PEN (polyethylene napthalate), PBT (polybutylene terephthalate), PMMA (polymethyl methacrylate), PLA (polyactide), polyhydroxy acid (PHA), thermoplastic urethane (TPU), or blends thereof. The two outer layers may be unfoamed skin layers having smooth outer surfaces, and the discrete inner foamed layers may be microcellular.
-15. (canceled)
A method for making a multi-layer foamed material sheet from a solid monolithic thermoplastic material sheet, the solid thermoplastic material sheet having a first bulk crystallinity level, the method comprising:
The method according to claim 36 wherein the fourth bulk crystallinity is at least 17 percent.
The method according to claim 36 wherein the multi-layer foamed polymeric object is in the shape of a cup or a tray.
The method according to claim 36, wherein forming the foamed thermoplastic material sheet includes heat-setting the shaped multi-layer foamed polymeric object, to thereby further increase the bulk crystallinity of the shaped multi-layer foamed polymeric object to a fifth bulk crystallinity level, wherein the fifth bulk crystallinity level is greater than the first, second, third, and fourth bulk crystallinity levels.
-28. (canceled)
(canceled)
Dependencies are inferred from the claim text.